OMG!!! Twins Rock part II

[TxDieselKid]

JTMc



The reason it was closed I think was because it got into a debate about rather Mark "slote" or "copied" the twin set up from a known system, rahter then how well they work or the fabing going into them.



None the less I have seen, and riden in the truck, and yes, they do rock!



Andrew

 

[fest3er]

Originally posted by Diesel Freak
... What happened?

Turbo RPM went from approximately 75500 RPM up to 87000 RPM. Compressor efficiency went from 75% down to 65%.

what does this mean?

May I, a complete novice, take a SWAG? Drive pressure is too high, so the WG should open a little?

Fest3er

 

[JTMcCracken]

TxDieselKid,

My question then is this, why is that not a legit topic to discuss? I believe it is, more so than many that are allowed(?) to continue. JTMcC.

 

[TxDieselKid]

I'm no moderator (yet, only if Slep Puller becomes one first ) but the thread title was "OMG Twins Rock!!", not "OMG I Stole Some Twins!!".



Not taking sides here, just from what I can see.



Andrew



P. S. still laughing @ "how much human waste have you produced in your lifetime" :-laf

 

[Briar Hopper]

Andrew, get it right, please... the "debate" was not whether Mark stole or copied a known system. He didn't.

It was about a certain person giving him information on the phone that he had no business giving out. That was "proprietary" information, and had been come by the hard way, with many thousands of dollars spent on research & development.

I am continually amazed by how much room for misunderstanding there is in the written words on these & other forums... .

 

[TxDieselKid]

Tom,

Thanks for setting it strat. Sometimes it's hard to understand things that are trying to be expressed with out saying them. Does that make since?



Tom I can understand where you are comming from.



Andrew

 

[Briar Hopper]

Thanks, Andrew... there were many more that misunderstood, though. I chose to "shut up" on that other thread, rather than fan the flames, as people thought I was attacking Mark personally. Not so. I took exception to one thing he did.

Diesel Freak's comments above, where he calls Holset "friggin *******s" for not releasing turbo efficiency maps to the public, to me seems to be totally representative these days, of the TDR members hostile viewpoint towards the very vendors that work hard to bring these products to market. Trade secrets are very much a part of all American business, like it or not. So is competition.

Once again, we are straying Mark's thread off topic. Not good...

We need to take this very debate to another thread, not this one. Or, even better, let it die down. Everyone has their own opinion, and no amount of debate will change that.

 

[T. Baker]

I have been reading all thease posts. I am all for Mark and grass roots engineering. Everyone told me I could not put a 6BT in my IH scout. It's a good thing I did not listen. The tractor pulling guys have been building twins and tripples for about 20 years now. Diesel hotrodding is a great hobby. Thanks for sharing your project with us Mark!

 

[Diesel Freak]

Originally posted by fest3er

May I, a complete novice, take a SWAG? Drive pressure is too high, so the WG should open a little?



Fest3er

nope... the wastgate would already be open. The turbo must spin faster to supply the engine at higher engine RPM. To turn the turbo faster, drive pressure must go up.



I have a theory... call it my 3^4 hypothesis



it states: For a turbo to be efficient on the Cummins ISB over 300 RWHP, boost pressure should be at least 30 psi, drive pressure should be no more than 30 psi at 3000 RPM.



ok everyone, time to get back on topic!

 

[Diesel Freak]

Originally posted by Briar Hopper

Diesel Freak's comments above, where he calls Holset "friggin *******s" for not releasing turbo efficiency maps to the public, to me seems to be totally representative these days, of the TDR members hostile viewpoint towards the very vendors that work hard to bring these products to market. Trade secrets are very much a part of all American business, like it or not. So is competition.

I was thinking about replying to this, but it really is not worth my time!

 

[Diesel Freak]

Holset could use some competition..... they are British. . remember the Boston Tea Party

 

[Diesel Freak]

I posted this on another thread, but I think it fits quite well here also.

you want information... well here it is



so, you want to size a seccondary turbo?



well, lets say that you want 1500 CFM (measured at the turbo inlet) and you want that air delivered to the primary turbo at 20 psi.



air has a density of 1. 205kg/m^3 at 20C, or



. 06565 lbm/ft^3 at 68F and one atmosphere (14. 7 PSIA)



20 PSIG means that thr turbo is operating on a PR of 2. 36



1500 CFM means that the turbo will move . 78 kg/sec of air.



so you want a turbo that will move . 78kg/sec of air at a PR of 2. 36 and you want it to do it effeciently.



The HX60 will barely do it!



Is there anything "proprietary" in this post?



NO! All this can be found on the internet!



Disclaimer: My figures are assuming there is no friction etc. etc, and some of them may be incorrect.



enjoy!

 

[DBR]

Mark, I’ve been semi-absent from the TDR lately and have just read your latest thread and the associated links with great interest…which brings me to my post. I just want to say good job and congratulations on “your own” twin set-up. I truly admire you for doing it yourself, just as I enjoyed the self-gratification of doing mine myself, I once again applaud you on “your” twin setup.

 

[Mark_Kendrick]

Again. . thanks for the kind words.



Looks like DF has been hitting the books lately. Good stuff.



I think geting the drive pressure to boost pressure measurements to be meaningfull will have to compare to the boost pressure before the the intercooler. The net effect is great but if you want to see how well the turbos are setup with an insufficient i/c you are urinating in the wind.



I would bet that my twins have much lower drive pressures than a singele turbo at 60psi of boost.



I know there is a large restriction in the intercooler because I almost never blow hoses off on the driver's side of the truck. To date the lower intercooler hose on the driver's has come off only once.



I've been looking into intercoolers and I think we need a 2000+cfm intercooler to prevent pressure loss at high boost/flow.



I don't know how the 5000rpm guys are getting air through the intercooler to make good power.



FWIW,

Mark

 

[Snow man]

Maybe its time for twin intercoolers to go with the twin turbos . Mark,if possible it would be informative to have a boost guage on the inlet of the intercooleras well as the one on the air horn now. ,so you could see what your boost loss is thru the intercooler,with that info you could determine exactly what the restriction is at whatever psi of boost there is on the inlet side.

 

[danandamy]

Intercooler efficiency vs volume and response

Ok, here's a question. Does there ever come a point that the intercooler becomes so much of a restriction that it surprasses any advantage that it gives you in cooling the air? In other words, is it possible that at some point you guys with big turbos or twins are pushing so much volume so fast that the gains from having the intercooler are out weighted by the amount of hair you could more quickly shove into the engine if the intercooler were not there?



dan

 

[Mark_Kendrick]

Dan,

I dunno. The heat shed by the i/c is pretty impressive even w/the decreased volume.

feeding 500* vs 150* air is a HUGE difference.



later,

Mark

 

[Diesel Freak]

Mark, any data yet?

 

[jlatham]

www.spearcointercoolers.com

They have custon intercoolers and commpreser maps.







Justin

 

[Diesel Freak]

Originally posted by jlatham

www.spearcointercoolers.com

They have custon intercoolers and commpreser maps.







Justin

yes they do, but the only usefull compressor map for our application IMO is the T-66 (close to an HX40)... it would make a great primary... ... feed it with a T-88 as the seccondary.